pgm: Handle NoWorkTreeException and IOException in Blame command

This avoids we show a stacktrace on the console by default when this
type of exception is thrown during the run method is executed.

Change-Id: I9290b057b004e9ee4137d968ba4f5759442aacb6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Blame.java

@@ -65,6 +65,7 @@ import org.eclipse.jgit.blame.BlameResult;
 import org.eclipse.jgit.diff.RawText;
 import org.eclipse.jgit.diff.RawTextComparator;
 import org.eclipse.jgit.dircache.DirCache;
+import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -134,7 +135,7 @@ class Blame extends TextBuiltin {
 
 	/** {@inheritDoc} */
 	@Override
-	protected void run() throws Exception {
+	protected void run() {
 		if (file == null) {
 			if (revision == null)
 				throw die(CLIText.get().fileIsRequired);
@@ -244,6 +245,8 @@ class Blame extends TextBuiltin {
 					outw.print('\n');
 				} while (++line < end && blame.getSourceCommit(line) == c);
 			}
+		} catch (NoWorkTreeException | IOException e) {
+			throw die(e.getMessage(), e);
 		}
 	}